Fluid recovery

ABSTRACT

After a rock anchor which encompasses the anchor bolt, has been inserted with an end sleeve beforehand into a bore hole, on the sleeve there is an adapter with liquid supply and drain. Via the holding pressure line a holding pressure is produced which fixes the adapter on the sleeve. Via the expansion line fluid flows into the anchor bolt and begins to fill it. The anchor bolt expands as a result of the pressure increase in the bore hole, so that its outer surface adjoins the bore hole wall and fixes the rock anchor in the bore hole. Via a gas supply connected to the adapter, a pressurized gas, before and/or after expanding the anchor bolt, can be introduced into the latter. The compressed gas is relieved after removing the adapter and routs the fluid located in the anchor bolt almost completely out of the anchor.

The invention relates to a device for expanding and/or evacuating parts of anchors, especially rock anchors of the friction tube anchor type or expandable friction tube anchor type, with the features of the preamble of claim 1.

Furthermore the invention relates to a process for evacuating parts of anchors, especially of rock anchors of the friction tube anchor type or expandable friction tube anchor type, with the features of the preamble of claim 8.

Moreover the invention relates to a process for setting anchors, especially rock anchors of the friction tube anchor type or expandable friction tube anchor type, with the features of the preamble of claim 16.

Anchors with expandable parts to be inserted into a bore hole are known for consolidating or securing rock and soil, for example in tunnel building or for securing slopes. These anchors, especially friction tube anchors or expandable friction tube anchors, are known as “Swellex” (manufacturer Atlas Copco MAI GmbH). As expandable parts these anchors have especially expandable anchor bolts with an outside surface in the expanded state adjoining the bore hole wall and thus fixing the anchor in the bore hole. The bolt can be expanded with water which is introduced with pressure into the anchor bolt by means of a pump via a removable adapter.

The air which has been compressed in the anchor bolt after the medium to be expanded, especially water, has been pressed in, causes the water to be pressed out of the anchor bolt again after removing the adapter. But it has been found to be disadvantageous for water to emerge uncontrolled and only partially again from the anchor bolt. A certain residual portion of water remains in the anchor bolt and together with the air contained in the anchor bolt promotes corrosion processes which adversely affect the service life of the anchor, especially a friction tube anchor.

The object of the invention is to make available a device and a process of the initially mentioned type with which the indicated disadvantages are avoided as much as possible.

This object is achieved with a device for expanding and/or evacuating parts of anchors, especially rock anchors, which has the features of the preamble of claim 1.

Furthermore this object is achieved with a process for evacuating parts of anchors, especially of rock anchors, which has the features of the preamble of claim 8.

Furthermore, this object is achieved with the process for setting an anchors, especially a rock anchor, which has the features of the preamble of claim 16.

Preferred and advantageous embodiments of the device as claimed in the invention on the one hand and the process as claimed in the invention on the other are the subject matter of the dependent claims.

In anchors, especially in rock anchors made as expandable friction tube anchors, with expandable parts (anchors of the “Swellex” type) and an adapter which is removably located on the anchor and which is connected via at least one fluid line both to a pump and also to the expandable parts, the adapter is connected as claimed in the invention directly or indirectly to a gas supply. Thus, pressurized gas can be supplied to the expandable parts for evacuation after they have been expanded (widened) and are at least partially filled with fluid. The gas expands in the expanded parts and presses the fluid necessarily out of the anchor. This process can optionally be repeated until the fluid has been completely removed. The corrosion processes which take place by the interaction of air and water in the anchor bolt can thus be almost completely stopped, with which the service life of the anchor is significantly increased.

As claimed in the invention the pressurized gas, especially compressed air, can be introduced both before and also after the anchor is supplied with the expanding fluid. For an artificially produced overpressure before supply with fluid, in contrast to known methods in which only the air volume which is under normal air pressure in the anchor is compressed, as the effect much less residual water remains in the anchor after pressure equalization. The fluid introduced into the expandable parts can be almost completely withdrawn in a controlled manner after expanding and optionally can be re-used to expand parts of other anchors.

Other details, features and advantages of the device as claimed in the invention on the one hand and the process as claimed in the invention on the other will become apparent from the following description with reference to the attached drawings, in which one preferred embodiment is shown.

FIG. 1 shows a schematic lengthwise view of one embodiment of a rock anchor.

FIG. 2 shows a cross sectional view of the rock anchor from FIG. 1,

FIG. 3 the rock anchor from FIG. 1 with an attached adapter and

FIG. 4 shows one embodiment of the device as claimed in the invention for expanding and/or evacuating parts of the rock anchor in a schematic.

FIG. 1 shows a rock anchor 1 in which the device as claimed in the invention and the process as claimed in the invention can be used. The illustrated embodiment corresponds to a expandable friction tube anchor as is known for example from U.S. Pat. No. 4,459,067 A and is also called “Swellex”. The rock anchor 1 is designed to be inserted into a bore hole and fixed in it to consolidate or secure rock and soil.

Essentially the rock anchor 1 encompasses a expandable part which on one end which is adjacent to the outer end of the bore hole (on the right in FIG. 1) has a sleeve 3 and on the other end is closed by an end sleeve 4. The expandable part can be especially an anchor bolt 2 which, as is apparent in FIG. 2, is formed by a tube folded to the inside in the lengthwise direction with an essentially omega-shaped profile. The anchor bolt 2 can be expanded by increasing the pressure within the folded tube so that the outer surface of the tube adjoins the bore hole wall and fixes the rock anchor 1 in the bore hole in this way.

In the sleeve 3 there is an opening, for example a hole 5, the function of which is described below.

Within the framework of the invention it is of course also possible that instead of the described friction tube anchor, other types and embodiments of anchors, preferably those of the initially mentioned type, can be used. One example is an embodiment which is known as “Swellex Hybrid” (manufactured by Atlas Copco MAI GmbH). This rock anchor is characterized in that several sections of rigid anchor rods/tubes are interconnected via coupling members and that on the (front) end of the anchor rod which has been formed in this way and which is inserted into the bore hole, there is simply a short segment of a expandable part like the anchor bolt 2 described above.

The rock anchor 1 can bear an anchor plate on its end which is located on the opening of the bore hole and the anchor plate is supported on the sleeve 3 on the soil or rock side.

After the rock anchor 1 with attached anchor plate has been inserted into the bore hole, there is an adapter 6 on the sleeve 3, as is apparent in FIG. 3. In one preferred embodiment, the adapter 6 as an inflation adapter is slipped or screwed onto the sleeve 3. The adapter 6 is connected to a pump 9 via a fluid line, especially an expansion line 7, and via a fluid line, especially a holding pressure line 8. To increase the pressure within the anchor bolt 2 the pump makes available a fluid working pressure (inflation pressure) of preferably 100 to 500 bar, especially 240 to 300 bar.

The fluid from the holding pressure line 8 within the adapter 6 presses two gaskets 10 together (holding pressure) such that the bulges of the gasket 10 which arise press against the sleeve 3 and tightly surround it securely against the inflation pressure. Then fluid flows from the expansion line 7 via a supply hole 11 to the hole 5 which is located in the sealed space between the two gaskets 10, enters the anchor bolt 2 and begins to fill it. In this connection, the omega profile of the anchor pin 2 is unfolded so that the outside surface of the anchor bolt 2 adjoins the bore hole wall and fixes the rock anchor 1 in the bore hole in this way. The anchor bolt profile attains a roughly round cross section with completed deployment at a fluid working pressure of roughly 240 to 300 bar.

Since the bore hole in practice has a smaller diameter than the completely expanded anchor bolt 2, it cannot completely deploy so that it presses against the bore hole wall while maintaining a lengthwise fold. The advantage of the lengthwise fold which has formed is that it increases stability by the resulting stiffening. By maintaining the working pressure over an interval of at least six seconds, the anchor bolt 2 is also pressed into irregularities of the bore hole wall and forms a frictional and positive connection.

FIG. 4 shows how the adapter 6 is connected to the pump 9 via the expansion line 7 and the holding pressure line 8. The pump 9 is in turn connected to a fluid supply line 12. In the expansion line 7 there is a valve 13 via which the inflow and outflow of fluid into and out of the adapter 6 are controlled.

Moreover it is provided as claimed in the invention that the adapter 6 is connected to a gas supply which in the illustrated embodiment is formed by another fluid line, especially a gas line 14, and a compressor 15. The compressor 15 can be an air compressor or can be connected to a compressed air tank. In the illustrated embodiment, the gas line 14 discharges proceeding from the compressor 15, not directly into the adapter 6, but ends in the expansion line in the region between the adapter 6 and the valve 13. In the gas line 14 there is a valve 16 via which the passage of gas is regulated. The valves 13, 16 and the pump 9 and the compressor 15 are controlled via a control unit 17.

As claimed in the invention the described device acts as a system for recovery of the medium which expands the anchor bolt 2, especially as a water recovery system. By means of the compressor 15, air which has been compressed via the adapter 6 can be pressed into the anchor bolt 2, which upon expansion routes the remaining, unwanted fluid portion out of the anchor bolt 2 into the expansion line 7. The pressurized gas, especially compressed air, can be introduced within the framework of the invention before and/or after supply of fluid to the anchor 1.

To introduce especially compressed air after expanding the anchor bolt 2, in particular after expanding the anchor bolt 2 the holding pressure, i.e. the fluid pressure, is held via the holding pressure line 8 for compressing the gaskets 10 and the inflation pressure, i.e. the fluid working pressure of preferably 240 to 300 bar, is reduced. At this instant in the process the valve 13 in the expansion line 7 is opened and the valve 16 in the gas line 14 is closed.

When the fluid has flowed/been expelled for the most part out of the anchor bolt 2, in the next step the valve 13 is closed and the valve 16 is opened so that gas, especially air, is routed via the gas line 14 and the expansion line 7 into the adapter 6, and thus into the anchor bolt 2. The holding pressure is maintained at this instant.

Subsequently, the valve 16 is closed again and the valve 13 is opened so that the gas which has been pressed into the anchor bolt 2 emerges via the expansion line 7 and in doing so presses the remaining fluid out of the anchor bolt 2.

The described processes can optionally be repeated until the fluid (for example water) is completely removed. To remove the adapter 6 from the sleeve 3, the holding pressure is lowered.

Analogously to the existing details, especially in the described valve positions with gas and fluid supply to the anchor bolt 2, as claimed in the invention it is also possible for especially compressed air to be introduced before expanding the anchor bolt 2 into the initially still empty anchor 1 which has been inserted into the bore hole.

Then the anchor 1 is supplied with the expanding fluid and is expanded by pressure. The profile deploys and the anchor 1 adjoins the bore hole wall with the formation of a frictional and positive connection. During this process the air which was injected previously is compressed. After expanding the anchor bolt 2 the adapter 6 is removed. The compressed air is relieved (pressure equalization) and routs the fluid located in the anchor bolt 2 out of the anchor 1.

In contrast to methods in which the air volume which is under normal air pressure in the anchor 1 is compressed, at the arbitrarily produced overpressure before supply with fluid, after pressure equalization much less residual water remains in the anchor 1. The interior of the anchor 1 is then almost dry.

The fluid emerging from the anchor bolt 2 can be routed from the pump 9 into a tank either via the drain line 18 or directly into a closed circuit.

In summary, one embodiment for setting a rock anchor 1 using the device as claimed in the invention and the process as claimed in the invention can be described as follows:

After a rock anchor 1 which encompasses the anchor bolt 2, especially an expandable friction tube anchor 1, has been inserted with an end sleeve 4 beforehand into a bore hole produced previously, on the sleeve 3 there is an adapter 6 with liquid supply and drain. On the one hand, via the holding pressure line 8 a holding pressure is produced which fixes the adapter 6 on the sleeve 3. On the other hand, via the expansion line 7 fluid flows into the anchor bolt 2 and begins to fill it. In this connection, the anchor bolt 2 is expanded as a result of the pressure increase (inflation pressure) in the bore hole, so that its outer surface adjoins the bore hole wall and fixes the rock anchor 1 in the bore hole in this way.

Via a gas supply which is connected to the adapter 6, a pressurized gas, especially compressed air, before and/or after expanding the anchor bolt 2, can be introduced into the latter. The compressed gas is relieved after removing the adapter 6 (pressure equalization) and routs the fluid located in the anchor bolt 2 almost completely out of the anchor 1. 

1. Device for expanding and/or evacuating parts (2) of anchors (1), especially rock anchors (1) of the friction tube anchor type or expandable friction tube anchor type, with an adapter (6) which is removably located on the anchor (1) and which is connected both via at least one fluid line (7, 8) to a pump (9) and also to the expandable parts (2), characterized in that the adapter (6) is connected directly or indirectly to a gas supply.
 2. Device as claimed in claim 1, wherein the gas supply is formed by a gas line (14) and a compressor (15).
 3. Device as claimed in claim 1, wherein the compressor (15) is a gas compressor and/or is connected to a compressed air tank.
 4. Device as claimed in claim 1, wherein there is a valve (13) in the fluid line (7) .
 5. Device as claimed in claim 2, wherein there is a valve (16) in the gas line (14), as is conventional.
 6. Device as claimed in claim 2, wherein the valves (13, 16) are connected to a control unit (17).
 7. Device as claimed in claim 2, wherein the gas line (14) discharges into the fluid line (7) in the region between the valve (13) and the adapter (6).
 8. Process for evacuation of fluid-filled parts of anchors, especially rock anchors of the friction tube anchor type or expandable friction tube anchor type, in which especially the device as claimed claim 1 is used, wherein pressurized gas is supplied to the parts (2) to be evacuated and wherein when the gas emerges from the parts (2) to be evacuated the fluid is routed out of them.
 9. Process as claimed in claim 8, wherein during supply and emergence of gas a holding pressure which acts on the adapter (6) is maintained.
 10. Process as claimed in claim 8, wherein to supply gas to the parts (2) to be evacuated the valve (13) in the fluid line (7) is closed and the valve (16) in the gas line (14) is opened.
 11. Process as claimed in claim 8, wherein after supplying gas to the parts (2) to be evacuated the valve (16) in the gas line (14) is closed and the valve (13) in the fluid line (7) is opened.
 12. Process as claimed in claim 8, wherein the fluid routed out of the parts (2) to be evacuated is routed in a closed circuit.
 13. Process as claimed in claim 9, wherein the holding pressure is lowered to remove the adapter (6).
 14. Process as claimed in claim 8, wherein the pressurized gas is supplied to the parts (2) to be evacuated before and/or after expanding the parts (2).
 15. Process as claimed in claim 8, wherein the pressurized gas in the parts (2) is relieved by pressure equalization and the fluid is routed out of the parts (2) to be evacuated.
 16. Process for setting anchors, especially rock anchors with expandable parts (2) of the friction tube anchor type or expandable friction tube anchor type, the parts (2) being expanded by means of a fluid by applying internal pressures, after they have been positioned in a bore hole which was formed beforehand, wherein the fluid is routed with gas supply out of the expandable parts (2).
 17. Device as claimed in claim 2, wherein the compressor (15) is a gas compressor and/or is connected to a compressed air tank.
 18. Process as claimed in claim 9, wherein to supply gas to the parts (2) to be evacuated the valve (13) in the fluid line (7) is closed and the valve (16) in the gas line (14) is opened. 